The NFL said on Monday the previous six-year collective bargaining agreement with the referees' union had expired and negotiations for a new agreement remained unresolved.
"In order to ensure that there is no disruption to NFL games this season we will proceed immediately with the hiring and training of replacement officials," the NFL said in a statement.
"Our goal is to maintain the highest quality of officiating for our teams, players, and fans, including proper enforcement of the playing rules and efficient management of our games."
The NFL said it still hoped to reach an agreement after both sides agreed to enter into mediation, including a negotiating session that took place over the weekend.
"We have great respect for our officials and in keeping with that view have made a proposal that includes substantial increases in compensation for all game officials," the NFL said in its statement.
In 2001, the league used replacement officials for one preseason game and the first weekend of the regular season, before reaching an agreement that was carried through to 2005 then extended until this year.